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rra s Ars Nrerum (DensionV JOHN s. GILBERT, or NEW vonk, N. Y.

FLOATING DRY-DOCK.-

Specifcation of Letters Patent No. 2,742, dated July 28, 17842.

To all whom t may concern:

Be it known that I, JOHN S. GILBERT, of the city and county of New York,in the State of New York, engineer, have invented new and usefulimprovements in floating dryfdocks for the purpose of raising vesselsout of water for repairs and also for the purpose of carrying loadedvessels or vessels without cargo over bars or shoals in rivers orharbors, which improved dry-dock I denominate the improved floatingbalance dry-dock; and I declare the following to be a full and exactdescription thereof.

`In constructing this dock of wood instead of iron I in the first placemake a platform of timbers of such length and breadth as may be requiredfor the class of ships for which the dock is intended, for vessels ofone thousand tons the width should be about sixty feet and the lengthabout one hundred and sixty five feet.

My mode of constructing this platform or bottom is as follows-If thebottom is to be sixty feet wide I take pieces of timber sixty feet longand treenail them together or if pieces of Vthat length cannot beobtained pieces of various lengths may be used avoidas much as possibleplacing the joints opposite to each other, when the requisite number ofthese cross floor timbers or lower clamps are thus fastened together tomake a platform of the required length and breadth I calk the seams withwedges of soft dry wood in this wav I make a platform perfectly watertight without the use of oakum. i The ends of the timbers that form thislower thickness are seen at -oof the drawing which is a perspectiveview. I in the next place build up the sides and ends as high as thedock will be immersed when finished which will be say about iive feet.My mode of building up the sides and endsthus far is to bolt regularcourses of thick timber one on the top of another. The first or lowercourse may be screw bolted to the platform, the end at which the vesselenters is left lower than the other as seen at -B I drive all the jointsmade by building up these sides and ends with wedges as beforedescribed, I then lay an-` other thickness of timber on the top of theplatform lengthwise of the dock and treenail one piece to another in thesame manner as the first and also bolt each piece down upon the lowerclamps #ct- This second thickness is wedged in the same manner as thefirst, the ends of this fore and aft platform is seen at I then bolt onupper cross timbers to form the rests for a cradle on which the weightof the vessel is borne and they also give additional transversestrength. -C- on the drawing. Willen the dock is thus far finished itmay be launched into the water. v

*clrepresents the riders or cradle on which the vessel rests. These areraised or lowered according to draft or weight of the vessel by doggingon more or less in number t-he object and uses of which will be morefully explained in another part of this specification.

Having made a substantial bottom` and sides as high as above describedof thick timber well bolted to the platform I put up the posts to formribs for theV outsides of the side camels or chambers, These posts areabout twenty two feet high. They are fastened at their lower ends to thecross timbers Q- and alsoto the thick work --B-- These posts are seen atll- They are also put up across one end of the plat-` form to form acontinuation of the outsides of the side camels and also to 4form oneside of a pumpwell at the end of the dock having put up sufficient postsalong the sides and across one end I plank the end up in the ordinarymode Of planking up ships.

The sides are planked up about twelve feet in the ordinary mode ofplanking up vessels; above this the sides are planked in sections onlyleaving openings for a passage through which to pass timber` and othermaterials to the vessel in the dock overrthe decks of the side camels;the sections planked up are seen at-s-and the openings are seenat-t-these openings are provided with gates that slide up and down ingrooves and they are each provided with a watertight tank which closesthe gate as the dock sinks and thereby prevents the sea heaving in andas the dock rises the tank follows the water down and again opens thegates; the tank attached to the gate is seen at u, I next proceed todivide the transverse section of the platform into three parts; themiddle division is set off of suiiicient width to give room between theside camels or chambers for the workmen to repair the bottom and sidesOf the vessel; the space left on each side for the side camels is seenat g and g2 and the space reserved for the These upper clamps are seenat i ship and workmen is seen at f. I next proceed to put up the poststhat form the inside ribs of the side camels or chambers; these ribs arebolted to the sides or stepped on to 5 the to-p of the upper clamps asmay be preferred and are seen at J the lower ends of both the inside andoutsidey ribs are supported by a timber bolted on to the upper clampsand running the whole length of the platform these inside ribs extend upon such an angle as shall give room for the workmen and at the same timeapproximate to Y the shape of a vessels bottom as nearly as possible;they sometimes are made to extend up on a straight line and are fastenedat their upper ends to the ribs that form the outsides of the sidecamels or chambers but in the drawing that accompanies thisspecilication they extend up about half way say twelve feet and arejoined to the outside ribs by a deck beam as seen at K. This form may bepreferable for steamships with paddle wheels on each side. I nextproceed toset up the ribs that form the inside of the end orcontinuation of the side camels; these may be put up exactly tocorrespond with the side camels but I generally set up po-sts about sixfeet from the latter end and make the end camel or forward pump wellextend entirely across the forward end of the platform. This arrangementwill divide this compartment from the middle and also from the sides.These inside ribs being planked up I build a tight deck in this v Pumpwell about seven feet above the bottom of the dock. This divides thepump well into an upper and lower hold. The pumps are cut through thisdeck and extend up to the top of it and no farther. They lift the waterinto the upper hold or chamber and fro-m it the water passes overboard.This lower hold or well' is seen at Z).

The forward end of the dock in the drawing is left without planking inorder to show the internal arrangements; the upper chamber and deck isseen at o; the pumps are seen at m; a gate to let the water out of theAunner chamber is cut through the forward end of the dock directlyopposite the pumps and even with the upper side o-f the deck r; thisgate cannot be seen in the drawing.

I-Iaving planked up. all the ribs and calked the planking the dock isdivided into four separate water tight vessels all joined together andhaving as yet no communication one with another. In the next placeproceed to the organization of the machine by 6o which all the parts aremade to act in concert or each one may be made to act alone in raisingor depressing.

I divide each of the side camels or chambers into vtwo or more separatecompartments by building up tight bulkheads across them fastening thebulkheads to the frames already described all the frames may bestrengthened by bulkheads or braces. In the dock which the drawingrepresents the camels or chambers on each side are divided into threeseparate compartments the middle compartment is small and is sometimesused as a pumpwell instead of placing the pumps at the camel or chamberthat connects the two side camels together this middle chamber is seenat -D- the bulkheads that form it are seen at -O- and -P-- a gate -liscut through the outside planking of this middle chamber, a gate -3- iscut through the bulkhead O- and a gate -lis cut through the bulkhead-P-.

The conductor -2- passes through the bulkhead -P- along the whole lengthof the compartment. g2 and through the bulkhead that divides the endcamel or compa-rtment from the middle of the dock, and this bulkheadalso divides the end from the side compartments, this conductor forms acommunication from the middle to the forward chamber for the passage ofwater, a gate -6- is made to close the end of this conductorua gate -5-is cut alongside of this conductor through the bulkheadl of thepumpwell-a gate -7- is also cut through this pumpwell bulkhead to admitwater from the`middle of the dock to the pumpwell-a gate is cut throughthe planking of the inside of the side camels directly opposite to thegate 1- by the two gates a passage is made for the water to pass fromthe outside through the middle chamber to the inside of the dock but asthe inside planking is left off to show the internal arrangements thisgate is marked 2.

The organization of the side camels are alike on both sides and allletters of reference are meant to apply to both sidesa platform is builton the top of the outside ribs and extends over the pumpwell and forms adeck. There is a deck across the cornerfor the engine house this deck isspotted off and is seen at -W- the platg form is seen at 7l/ It will beseen that I can use my dock for lifting vessels out of water without agate to inclose the vessel for any reasonable amount of lifting powermay be obtained by the side and end camels or chambers by raising mycradle in the manner heretofore explained in this specification and Ineed not of necessity have a tight bottom yet in all cases I think itbetter to have a tight bottom and a gate to inclose the vessel, becauseif the vessel proves very heavy I have a reserved power which I canbring to bear up the vessel and because I can exclude the action of thewaves the inclosing gate y' seen at -fn/- the wicket through which thewater passes out as the side camels are exausted and in which the dockis sinking is seen at a2- this entrance gate may be made to fold byhaving the upper part hung with hinges as seen at -v-e,

Having constructed my improved floating balance dry dock in mannersubstantially as herein set forth and described, I use it for dockingvessels in the following manner: When I sinkit for the reception of avessel I open the gates l-B-l that communicate with the middle tank oneach side I then openthe wicket gate -x- I then open the t3- and 74- oneach side this allows the water to pass into all the separatecompartments of dock, as it sinks I shut the gate that communicates withany part that sinks too fast and thereby preserve the equilibrium whenthe dock is low enough for the reception of the vessel all the gates areclosed and the main or entrance gate is opened this entrance gate isfurnished with ballast suilicient to sink it the ballast being placedoutside of the center upon which the gate turns it opens of itself whenthe tackles are slacked the vessel is then hauled in and placed as nearthe middle as possible. The gate is then closed behind the vessel theWicket -azbeing left open the pumps are started and the water isexhausted wholly or in part from the side and end camels or chambers andas the dock rises with its load the water passes out at the wicket fromaround the vessel the equilibrium of the dock being maintained by takingmore or less water from any particular compartment by means of theconductor and the gates as already described in the process of sinking.

The height to which the vessel will be lifted above water by the powerof the chamber or camels on the side and at the end will depend upon theheight of the cradle but in most cases it will be found better to closethe wicket and pump out the middle, the platform on which the workmenstand to repair the bottom of the vessel is made to float.

Thus far I have described my dry dock as being capable of sinking by itsown weight but I sometimes sink it to great depths by pumping water intothe side camel. My mode of sinking it in this way is very simple. Thereis a gate in the forward end of my dock to pass the water out of theupper chamber -fvinto which the pumps lift the water this gate beingclosed and the gate -7- being opened the chamber cwill be iilled by thepump. I then open the gate 8 and pass the water by other conductor Q,and the gate in the side camels to any compartment required. The gate 7is closed when the gate 8 is opened.

Having fully described my improved floating bottom dry dock and also themode of using it, I do not claim simply making and using camels placedagainst each side of a vessel and by which she is raised and floatedover shoals, they having been used before my invention-neither do Iclaim making and using a floating dry dock with tanks, or trunks, oneach side divided into separate compartments by tight bulkheads becausethat kind of dry dockI have patented and further I do not claim simplyuniting the separate compartments of a float with a pump will by meansof pipes governed by cocks or valves as this has been patented, but inthe patent referred to the separate compartments of a float are unitedwith a pump well the dock being composed of a series of such floats onthe tops of which the vessel rests but Vhat I wish to claim as myinvention and desire to secure by Letters Patent is- 1. The method ofconnecting all the chambers or separate compartments on each side of thedock with vthe pump well by means of pipes or conductors governed bycocks, gates, or valves whereby all the separate compartments are madeto :act in concert or alone or any number of them in depressing orraising the dock in manner substantially as herein described, and I wishit distinctly understood that I claim this arrangement whether appliedto docks with two side camels united together or to side camelsdisconnected.

2. I claim the dividing the camels into an i JOI-IN S. GILBERT.

Witnesses ISAAC BEERs, WM. CHASE.

